Experiment 1

It's the start of "real" physics activities. We used a very high tech device than can produce an instant graph of velocity and distance over time from a detector of motion. It can produce the trend line of selected area of the graph. At first we detect the motion of a free falling ball and the motion of falling picket fence. A picket fence is a strip of glass with black stripes of equal spacing. As it passes through a detector, the detector detects how fast it is falling by detecting the motion of these stripes.

The first experiment, the free falling ball test is quite harder and sometimes give bad results. You have to throw the ball upward many times to get the result you want. Sometimes when your hand is exposed to the detector , you can get an unwanted result. The other one is quite easier because it gives a unique graph and is smoother compared to the one produced from the first one.

We did fifteen trials each test and all gives results of acceleration close to the value of g, the acceleration due to gravity. System error, and outside factors give small deviations from the real value.

January 9, 2011

We were taught on how to graph a scatter plot. A scatter plot should have an x and y axis labels and the units should be indicated, and the title (y vs. x). A caption may also be written. the range of the graph should be chosen for maximum readability. It means the points on the graph should not be too small nor too big. The y axis should be the dependent variable and the y axis should be on the x axis.
I also learned about how to put error bars on the graph that represents absolute uncertainties of a data point. the data points represents the expectation values. Below is an example of a scatter plot.

Trend lines and linear fits can also be drawn on the graph and the equation of the line should be written.

Activity 4

In this lecture we were taught how to get the measure of central tendency.. From a data set the mean of that data set would be the average value from the data set or the center of zero deviation. It means that subtracting each data from the data set to the mean and summing them all up you should get 0. The mode would be the "most frequent" data value. But mode can be more than one in a data set. so it is also defined as that data value that are at least as frequent as the other data value provided that not all data values are equally frequent.
The median is the "middle most" value. But for data sets that have even no., the median cannot be simply pointed out from the data set. And so, it was defined to be that data value such that at most 50% of the data is less than its least 50% of data is greater than or equal to it.
To get the coordinates (x,y) of the centroid which is the center  point of your scatter plot, the x coordinate would be the sum of all x coordinates of the all the data divided by the number of x. Same is for the y coordinate.
To get the best fit line, draw a line from the centroid to the origin and it will be represented by the linear equation y= mx + 0. The slope of the best fit line can also be found by getting the anything from these: ratio of medians, median of ratio, ratio of arithmetic mean, arithmetic mean of ratio, or regression through origin least square. All can give the exact value of the slope except for the ratio of arithmetic mean that can give a slight deviation from the actual value of the slope.

Activity 3

Calipers were the most precise measuring instrument I've ever used. We were taught how to use it in hiugh school and I've already forgot how to use it. One thing I've learned about calipers from this lesson is to how to fully utilize it's parts and functions to get a more precise measurement.Good thing we have physics 101.1. We had an activity on using calipers and I enjoyed measuring the thickness of 30 rice grains.

Activity 2

Wow! things get harder and harder. i thought on the first activity that it's all that we need to report data. But here comes activity 2. Error and error propagation. One type of error aside from the uncertainty was introduced. It's the deviation. And it makes things more complicated together with the addition of the absolute and relative errors. I've learned here how to add subtract, multiply or divide on best estimates. It's quite confusing because in adding or subtracting  you should use absolute uncertainty and in multiplying and dividing, relative uncertainty should be used. It also bacame harder when we computed multiple operations on best estimates. the differences between precision, accuracy, acceptability, and practicality are also explained. Then our professor gave us homework on other methods of estimates and errors. Because it uses statistics, I cannot understand many of these things.

Activity 1

It's the only time I really understood why we need the concept of significant figures. For example the value 2.3 is very differrent from the value 2.30 because 2.3 means not 2.2 and not 2.1. On the other hand 2.30 means that its not 2.29 and not 2.31. Uncertainty is always present when measurements are done based on the accuracy of the measuring tool that is why significant figures are really important. Another thing I only fully understood from this lesson is to how to find the significant figures of multiple operations. The part where we approximate the order of magnitude of the number of hair in the human person is the one  I really enjoyed. Fermi questions.... that's new to my ears and it sounds amazing especially when I heard that some people make it their hobby to approximate the magnitude of amount that are impossible to count. Another new thing is about the second order of approximation or the best estimate. Now I knew why trials are important to values that are changing and how to get the best estimate using the values from the trials. When the trials have values that are far from each other maybe you are doing somrthing wrong. That is why I also learned the technique to know whether you are doing the right thing in the experiment. Not like when I was in high scholol, we usually disregard the importance of trials and just give the value of the 2nd and other trials equal to the value of the 1st trial even though they were not exactly equal.

First day

As usual, we introduced ourselves and I introduced myself as a student from Benigno "Ninoy" S. Aquno High School, a not so popular school because it's just an ordinary public high school. I also said that I have chosen to be a physics major because of my teacher in physics and I want to prove that even if physics is a though subject, I can still do it. Then our professor explained what are we going to do for the rest of the semester. He explained the course outline. I didn't really understood all of it but one thing I know is that it will be going to be exciting as it goes on and our skill will be truly enhanced